Disk harrow



April 7, 1953 Filed Oct. 11, 1948 Jfvl.

O. W. DOMRIES DISK HARROW 2 SHEETS-SHEET l April 7 1953 o. w. DoMRlEs 2,633,686

DISK HARROW Filed oct. 11, 1948 2 SHEETS-SHEET 2 n satisfactory.

Patented Apr. 7, 1953 UNITED STATES PATENT 'OFFICE DISK HARROW Otto W. Domries, Anaheim, Calif.

Application October 11, 1948, Serial No. 53,854

Claims.

1 This invention relates to earth cultivating apparatus of the type commonly referred to as disc narrows or disc vplows, and has to do more particularly with discing apparatus employed in conjunction with ground wheels upon which the discing apparatus may be carried for the purpose of transport or when making turns in the field.

Heretofore, when using most types of disc harrows or disc plows, there *has been diiiiculty in transporting the same and in making turns in the field because of the fact there has been no means for lifting the discs from the earth being cultivated, and in connection with other forms means for supporting the discs in elevated position above the earth have not been entirely It is, therefore, an object of this invention to provide a structure for disc plows, or disc harrows as the term will be used hereinafter, which will be thoroughly satisfactory for elevating the discs from the soil for the purpose of transport from place to place or for any other purpose including thev making of turns.

Another object of the invention is to provide a wheeled carriage of novel construction upon which all or a portion of the weight of the discs and their supporting frames may be-easily disposed as desired, and penetration of the discs into the soil regulated as required.

A still further object is to provide in a disc harrow having ground wheels a structure by means of which the discs may be automatically drawn into the conventional diverging arrangement when they are lowered into operative position on the soil and forward movement of the tractive vehicle pulling the ysaine is commenced.

It is also an object of the invention to -provide Vmeans which may be easily operated by the tractor driver for the purpose of raising and lowering the discs at will.

An additional, object of the invention is to provide positioning means interconnecting the frames which carry the' disc so that the relative positions of the frames and their discs may be automatically established at the will of the Ytractor driver. f A Y Still another object of the invention vis to provide in a disc harrow an overhead supporting means for the discs and their frames which may vbe raised and lowered for the purpose of raising the discs and their frames as desired and which will at the same timehold such frames and discs appropriately balancedin a substantially horizontal relationship. L 1 .1

A particular object of the invention is to provand a conventional` tractor;

2 vide a disc harrow having ground wheels for the purpose of supporting the lsame in elevated position by means of which forward and vrearward gangs of discs carried upon forward and rearward frames may be automatically shifted into operative position or into transport position by the simple expedient of moving a tractive vehicle slightly forward or slightly rearward to effect the respective adjustment.

Additional objects are to provide novel means for limiting soil penetration and for varying the relative operating elevations of ground wheels with respect to the discs when one wheel works in a furrow.

Other objects, and theV various features of construction of the invention, will become apparent to those skilled in the art upon reference to the following specification and the accompanying drawings wherein one preferred embodiment of the invention is disclosed by Way of illustration.

In the drawings:

Fig. l is a plan view illustrating the various Aparts of the apparatus in discing position;

Fig'. 2 is a side elevation illustrating the parts in the relationship shown in Fig. 1 as viewed vfrom the left side of the apparatus as it proceeds .f forward, such forward direction being toward the `left side of the sheet;

Fig. 3 i-s a diagrammatic plan View illustrating the draft connection between the harrow of Fig. 1

Fig. 4 is a plan view similar to that of Fig. 1

but showing the'parts `in transport position, the

frames carrying the discs being drawn into parallel relationship from the diverging, discing vposition'of Fig. 1;

Fig.5 is ya fragmentary elevation on anen- .larged scale, the view being taken approximately from the line 5 5 of Fig. i from which two operating levers and associated linkages have been omitted to facilitate the showing of the other mechanism of Fig. 4; and

Fig. 6 is an enlarged detail in elevation substantially as indicated by the line 6-6 of Fig. 4. As seen in Figs. l and 4, the major parts of -the apparatus illustrated are a forward disc frame I0 having conventional discs Il, a rear- Ward disc frame l2 having conventional discs i3, an overhead lifting and spacing beam it whose ends are pivotally attached to the central portion of the disc frames i0 and I2 by means of vertically disposed pivotal mounts I5, a diago- .nally disposed; connecting vand positioning bar it whoseends arerpvotally attached at i7- to the respective frames l0 and l2, a right ground conventional tongue 2! attached at its forward end to a conventional tractor 28 by means of a conventional pivotal mounting 29 as seen in Fig. 3.

Each of the forward and rearward disc frames iii and I2 is conventionally constructed with a front rail 35 and a rear rail SI, the respective front and rear rails 3E) and 3l being connected by end bars 32 and by brackets 33 which serve both to rigidify the frame and to provide mountings on dependent portions thereof for shafts 33a which carry the discs II and I3 in a conventional manner. In addition, the rear rail 5I of the forward disc frame I@ and the forward rail 3G of the rearward disc frame I2 are respectively provided near one end with laterally projecting anchor strips 34 which may be in the form of short angle irons welded to the respective rails and carry the pivots i for the connecting and positioning bar i6 which extends diagonally across the structure, as will be seen in both Figs. l and 4, so that pivotal movement of the disc frames I and I 2 on the pivotal mounts I will be synchronous and so that pivotal movement of one frame in one direction will be imparted to the other frame in the opposite direction. This of course is Vdue to the crossing of the spacing beam i4 and the positioning bar i E and the crossing of the respective lines of pull.

In addition, each of the disc frames Ill and l2 is provided adjacent its middle with a rigid transverse carrier plate 35 which in practice is a channel bar` having its ends welded to the respective rails 30 and 3l, the middle portion of each carrier plate providing anchorage for the respective pivotal mount l5 at the respective end of the overhead lifting beam I4. Each pivotal mount I5 is in the form of a heavy upstanding stud 35 whose lower end is rigidly secured to the respective carrier plate 35 and whose body portion is received in a heavy sleeve 31 and held in operative position by an appropriate head 35a on the top of the stud. Each sleeve 31 in the form shown is rigidly attached to the respective end of the overhead lifting Vbeam I4 by being welded to an upstanding plate 38 whose upper portion is in turn welded to the end of the beam i4 as indicated at 33a in Fig. 2. As indicated in Fig. 5, the beam I 4 may be of heavy tubular construction and the attaching plates 38 are intended to close the open ends of the tube.- By the means illustrated in Fig. 2, the disc frames l0 and l2 swing upon the pivotal mounts I5 as centers by reason of the rotation of the studs 35 in the sleeves 3?, and when the lifting beam i4 is raised by the hydraulic elevator 24 the disc frames I 0 and I2 are lifted through the medium of the heads 36a on the studs 3S by reason of the fact that the head 35a overhangs the sleeve 3i' in each instance and thereby serves as a lifting agency.

The carriage means 22, which supports the lifting beam I4 upon the axles 25 and ZI through the medium of which the Weight of the lifting beam I4 and the disc frames I0 and I2 is transferred to the ground wheels I8 and I9, comprises, in the form shown, a rigid yoke 45 which extends transversely of the lifting beam i4 and of the harrow structure and has its middle portion welded, as indicated at 4I, to the underside of the lifting beam I4. This yoke 42 is of con paratively wide strap material of somewhat arcuate formation, and its ends are directed downward to a position adjacent the axles 2@ and 2l. Each end of the yoke 40 has secured thereto an angular attachment bracket 42 of conventional angle material whose upstanding web is welded to the adjacent yoke and whose horizontal web rests upon the transverse body portions of both the axles 25 and 2|. The angular attachment brackets 42 are secured to the axles 25 and 2l as by means of U-bolts 43 as best illustrated in Fig. 5, these bolts serving as bearings for the axles.

In order to mount the hydraulic elevator 24 in proper position between the lifting beam I4 and the ground wheels I8 and I9, mounting arms 45 which act as lever arms are welded to the body portion of the forward axle 20 in position to extend approximately horizontally forward when the parts are in an intermediate relationship such as that illustrated in Fig. 5. The forward ends of the mounting arms 45 are apertured to receive trunnions 46 which project laterally from the sides of a base 4l provided on the lower end of a hydraulic cylinder 43 which is mounted in an uprightrposition as seen in Fig. 5 and has projecting upwardly therefrom a piston rod 49 whose lower end is operatively disposed within the cylinder 46 for the purpose of carrying a piston 50 orV the like. The upper end of the piston rod 4S projects through an opening 5| in the underside of the tubular lifting beam I4 so as to receive a transverse pivot bolt 52 0r the like which extends through the sides of the lifting beam I4 and acts to provide a pivotal mounting for the upper end of the piston rod 49.

The piston rod 49 and its piston 55 in the cylinder et of the hydraulic elevator 24 are controlled through the medium of a pump lever 54 and a bleeder valve handle 55 positioned approximately as seen in Fig. 5. The lower end of the pump Ilever 54, which is in the form of a bent lever, is

fulcrumed at 56 on the upper end of a bracket 5'? secured to the hydraulic cylinder 48, the lever 54 actuating any appropriate pump means, such as a plunger 58, through the medium Vof any bearing member such as the depending boss 53a illustrated. The pump lever 54 is adapted to be actuated through the medium of a cable attached to the upper end thereof and extending forward-to the drivers seat, approximately as indicated in Fig. 2, whereby to operate the plunger 58, the lever 54 being automatically returned to its initial position as by means of a spring En (Fig. 5)'disposed about a guide stem el whose upper end passes loosely through any appropriate guide 62 on the lower end of the lever 54 and whose lower end is mounted upon a pivot 63 carried on a bracket 64 extending forward from the lower portion of the base 47 of the hydraulic cylinder 48. l

The handle 55, which is provided for the purpose of actuating a bleeder 55 at the base of the hydraulic cylinder 48, is in the nature of a lever fulcrumed at 66 on the forward end of the bracket 64. The lower end of the handle 55 is vconnected to andractuates any appropriate linkage generally-indicated at 61 which is nxed to the outer end of a rotary valve stem 68 leading to the bleedervalve55. The handle 55 also is operated by the tractor driver bymeans of a cable or the like, as indicated in Fig. 2 and it is adapted to be returned to its initial position of Fig. 5 Aeither by gravity or by means of any appropriate spring device, not shown.

From the foregoing it will be apparent that by drawing forward the upper end of the pump lever 5ft the plunger 5t, or similar pumping means, Will be actuated to introduce hydraulic nuid under the piston 5B for the purpose of elevating the piston rod 49, the lever 54 being returned automatically by the spring 68. Such operation of the lever 54 repeatedly serves to expel the piston rod 49 to whateverextent required, whereby'to separate the lifting beam It and the outer ends of the lever-like mounting arms 45, thereby pushing the lifting beam I4 upward with respect to the ground wheels i3 and I9. The lifting of the beam I in turn lifts the disc frames Il) and I2 through the medium of the heads 35a. on the studs 35 (Fig. 2) of the pivotal mounts I5. By slight actuation of the valve handle 55 toward a position such `as illustrated in Fig. 2, hydraulic fluid under the piston 58 may be relieved to any extent desired, thereby lowering the lifting beam It and the -disc frames Ill and I2 as required and to regulate the penetration of the discs II and I3 into the soil (see Fig. 2) as deemed best. a

For the purpose of positively limiting the descent of the lifting beam Ill and the disc frames 4lil and I2, an adjustable stop device is employed which is illustrated in Fig. 6, such stop device includes a heavy stop arm 'Ill which is horizontally disposed with its forward portion projecting forward from the rigid transverse yoke Lit, its rearward portion being welded to the yoke 48 at a position somewhat laterally disposed from the lifting arm ld as seen near the center of Fig. 4. This arm l and associated parts are omitted from the other figures to avoid confusion. The arm lil is disposed immediately above a short lever arm l2 welded to the forward side of the adjacent axle 20. The lever arm l2 has rigidly mounted on its upper face at its forward end a screw 'I4 upon whose upper end there is rotatably mounted an internally threaded sleeve v.l5 having handle means 'i6 whereby-the sleeve 'l5 may be vertically adjusted on the screw 14 as desired. With this stop device, the spacing between the upper-.end of the sleeve 'l5 and the underside of the adjacent portion of the horiaontal stop arm "lil may be predetermined for correspondingly limiting-the descent of the discs Il and I3 into the soil in accordance with the nature of the soil or the character of the cultivation to be given to it. y

Means is also provided `for varying the elevau tion of one of the ground wheels with respect tor the other, as when it is desired to maintain the disc frames I 8 and i2 and their discs II and I3 in a comparatively horizontal working position while the left ground wheel i9, for example, travels in a furrow produced by the disc I I immediately in front of it and while the right ground wheel I6 travels upon the loose earth that has been lled into a corresponding furrow formed by 4the immediately preceding right disc 'il through theearth shifting action ofthe nearest disc Il when the harrow parts are in the operative relationship seen in Fig. 1. Such means for varying the relative elevation vof the ground wheels I8 and I9 is best seen in Fig. 5. It comprisesV an upstanding arm ,8G rigidly` attached to 'the transverse body portion of the axle T20 and a cooperating upstandingarm BI rigidly attached to the body portion of the axle 2l of the left ground Wheel Ill.v A position regulating link 82 connects the upper ends of the upstanding arms 8U and 8|, and in the form shown, the rear end of the link 82 is pivoted at 83 lto the upper end of the arm 8|, the forward end of the link 82 loosely projecting through an eye 84 on the upper end of the arm and threadedly receiving on its outer end an internally threaded sleeve 85 having handle means 86 or the like for rotatably vadjusting such threaded sleeve 85. It will be apparent that, as the sleeve 85 is threaded along the link 82 to shorten the effective length of the link 82, the upper ends of the opstanding arms 80 and 8 I will be drawn together and the laterally disposed arm Zla. of the axle 2| will be depressed with respect to the laterally-disposed arm 20a. of the axle 20, so that the left ground wheel IS may assume a lower position with respect to the horizontal plane of the axles 2li and 2| and the right ground wheel I8. Since the position of the laterally disposed arm 29a of the axle 2l) is fixed by the hydraulic elevator 24 through the medium of the mounting arms 45 rigidly attached to the axle 2D, the position of the upstanding arm 80 on the axle 20 likewise is fixed. Therefore, the

vadjustment of the length'of the link 82 is, in

effect, imparted through the upstanding arm BI to the lateral axle arm 2m' and the left ground wheel I9. By such means the transverse body portions of the axles 20 and 2l and the disc frames I and I2 are maintained in a level or horizontal position when the left ground wheel I9 travels in a furrow. In order to insure maintenance of the frames I U and I2 in such horizontal position, it is preferable that their weights on opposite sides ofthe pivotal mounts I5 be balanced as well as possible.

In order that the di'scfraines Ill and I2 and their discs II and I3 maybe easily drawn from the inoperative or transport position of Fig. 4 into the operative discing position of Fig. 1 merely by draft from the tractor 28 or other tractive vehicle, the previously described pull link 25 has its rearward end attached by a vertical pivot bolt 80 or the like to a forwardly extending ear 5l on the forward side of the front rail 3l] of the rearward disc frame I2. 'The forward end of the pull link 25 is passed loosely through an elongated guide loop 92 on the front rail of the forward frame I0, so that such forward end of the pulllink 25 may slide freely through the guide loop 92 between the position of Figs. 1 and 2 and the position of Fig. 4. The forward extremity of the pull link 25 rigidly carries a depending arm 94 (Fig. 2) whose lower end is attached by aclevis 35 to' the leftl end of the draw bar 2%. the opposite end of the draw bar 26 being connected by a clevis 95 to a depending bracket arm 9'! rigidly secured to the forward face of the front rail 3D of the forward disc frame It. Thus, when draft by the Ytractor 28 is transmitted to the draw bar 2S by the tongue 2l and a brace 98 Fig.`3), the pull link 25 operates upon the left end of' thefrearward disc frame l2 to draw it forwardfrom its'position of Fig. 4 to its position of Fig. l' until checked by some means such asa vertically disposed stop holt orzpin Iil (Fig. 1) selectively disposed in'any one of a plurality of holes I0 I in the pull link 25,v such pin Ill being adapted tol strike the rear edge of the guide loop 92 andpreferably the rearedge of the adjacent front rail.38.1 i.

As a consequence of the forward movement of the left end of the rearward disc frame I2, a corresponding rearward movement of the left end of the forward disc frame I takes place by reason of the pull imparted by the diagonally disposed connecting and positioning arm I6. By arranging the parts substantiallyas illustrated, `the forward movement of the clevis 95 is substantially equal to the forward movement of the clevis S as the frame I0 swings about its pivotal lmount I5. Thus, the draw bar 26 is always substantially parallel to the body portions of the axles 20 and 2|, and as a consequence the braced `tongue 27 extends forward in a position substantially parallel to the line of travel.

When the harrow parts are in the usual discing position somewhat as shown in Fig. 1 they are also in an appropriate position for-making a left turn. However, the forward discs l I are not in good position for making a right turn, inasmuch as 'they would then bend to gouge flatwise into the earth. To overcome this difficulty, a drag chain |62 or the like, has its rearward end attached to a lug |03 on the left end of the forward side of .the front rail of `the front disc frame I6, the forward end `of the chain H32 being adjustably secured in an .appropriate slot or other retaining mea-ns carried by a lug |04 near the left end of a horizontal guide rail |25 conventionally provided on the rear of thetractor 2E. Thus, when the tractor 28 turns to the right and swings the left end of the rail |05 and its lug |94 to the left with respect to the pivotal mounting .22 cf the tongue 2T, `the chain |02 is correspondingly pulled forward thereby pulling forward the left end of the forward disc frame it so that the parts are moved from the position of Fig. l to the position of Fig. 4, thereby placing the parts inV better relationship for the right hand turn. Placing of the rearward disc frame I2 in such position is effected through the medium of a draft action produced by the connecting and positioning bar I6 which acts to swing the frame I2 about the rearward pivotal mount I5 on the lifting beam I4.

Operation As will be apparent from the foregoing description, when the parts are in the operative position as illustrated in Figs. 1 and 2, actuation of the pump handle 54 by the driver of the tractor 28, as through ythe medium of a cable extending forward to the tractor as indicated in Fig. 2, Voperates' the hydraulic elevator 24 `(Fig. 5) so that the piston rod 49 and piston 50 are elevated with respect to the hydraulic cylinder 48, thereby elevating the lifting beam I4' and raising with it the balanced forward and rearward disc frames l IIJ and I2.' This result is accomplished by reason of the fact that the arms |55 which carry the hydraulic cylinder 58 at their forward ends serve as lever means working through the transverse body portion of the forward axle 20, so -that the ground wheels I8 and i9 tend to be depressed with respect to the carriage 22. As a consequence, the carriage 22, including its transverse yoke 50, and the lifting beam I4 are elevated. By reason ofthe adjustable connecting link 82 on the upsta'nding arms 8f! and 8|, Fig. 5, the axle 2| and the ground wheel I9 are caused to operate in unison with the axle 20 and the ground wheel I8. Y.As previously stated, adjustment of the effective length Vof the link 32 through the medium of the threaded sleeve B15 provides for `travel of the left ground wheel |97, for example, at a lower vlevel in a. furrow than the level of the ground wheel I8 on soil filling a furrow, whereby to maintain the disc frames and their discs substantially horizontal when in discing position. When the frames I0 and I2 are raised from the discing position, and it is desired to transport the vehicle on a roadway, the threaded sleeve may be adjusted to vary the effective length of the linkage 82 and level the wheels I8 and I9 with respect to the frames.

For the purpose of transport, the lifting beam i4 and the ydiscs frames Il! and I2 having been elevated by operation of the hydraulic elevator 24, as above described, a rearward thrust applied to the pull link 25, as by .backing the tractor 28, forces rearward the left end of the rearward disc frame I2, and a. corresponding forward movement of the left end of the forward disc frame IG is imparted by thrust applied through the right end of the rearward disc frame I2 and the connecting bar IE to the left end of the forward disc frame lli, so tha-t the parts assume the position of Fig. 4. By then dropping a stop pin I00a into a forward hole IBI in the forward end of the pull link 25 as seen in Fig. 4, pull imparted to the forward end of the link 25 when the tractor moves forward is transmitted to the mentioned stop pin I Illia and through it to the adjacent loop 92 and the left end of the forward rail 3l of the forward disc frame I0, the parts thereby maintaining the relationship shown in Fig. 4 upon forward travel.

When it is desired to return the parts from the transport position of Fig. 4 to the operative discing position of IFigs. 1 and 2, the stop pin H3201I is withdrawn and the valve handle 55 is pulled forward by the operator of the tractor to actuate the bleeder valve 65 and allow the lifting beam It. the disc frames I land I2 and their discs I I and I3 to descend into the operative position, as seen in Fig. 2. `As previously indicated, the amount of penetration of the discs may be limited by the adjustable device shown in Fig. 6, the threaded sleeve 'I5 being adjusted on the screw 74 to space the upper end of the sleeve I5 from the stop arm 'Iii in accordance with the desired amount of earth penetration by the discs. The stop pin it!) of Fig. 1 is then placed as desired in one of the holes IUI in the pull link 25. Upon forward movement of the tractor 28, draft upon the draw bar 253 tends to swing the right end of the forward disc frame I0 forward to the position of Fig. 1 by draft action imparted through the clevis 96, and draft upon the pull link 25 by way of the clevis e5 causes the left end of the rearward disc frame I2 to be moved forward until the stop pin |98 strikes the rearward edge of the guide loop S2 on the front rail of the forward disc frame I at which time the stop pin |03 also preferably comes into engagement with the rearward edge of such front rail 35. Under these conditions, the connecting and positioning bar IE functions to limit and control the relative movements of the disc frames I!) and I2 and thereby establish the desired positions of the parts somewhat as illustrated in Fig. 1. When the end of an excursion across a eld has been reacheda left turn may be easily made with the parts remaining in the position of Fig. 1. When Va right turn is commenced, the swinging of the lug I D4 (Fig. 3) on the guiderail I o5 places a draft upon the chain |32 which pulls the forward dise frame I0 up to the position of Figs. 3 and 4 and shifts the discs I I and i3 correspondingly, thereby facilitating the turn. Also, a right turn 9 may be made easily by rst actuating the pump lever 54 to elevate the lifting beam ILE and the disc frames and their discs, whereupon the right turn is made with the load being carried by the ground wheels I8 and i3.

It is intended to cover all variations of the generic invention herein disclosed which fall within the scope of the claims.

I claim as my invention:

1. A wheeled disc hai-row structure comprising: a forward disc frame; a rearward disc frame; a pair of ground wheels respectively disposed at the sides of said structure near the ends of said frames; axle means for said wheels; a carriage supported by said axle means; an overlying spacing and lifting median beam having its ends attached respectively to middle portions of said frames to lift the latter and having its middle portion supported and carried upon said carriage, said overlying median beam constituting the sole connection between said disc frames and said carriage; lever means connected with said axle means and directly underlying said beam; and elevator means disposed between and connected with said lever means and said beam for raising and lowering said beam and frames with respect to said wheels.

2. In combination in a wheeled disc harrow structure: a forward disc-carrying frame; a rearward disc-carrying frame; a pair of ground wheels; a pair of axles having longitudinally extending arms upon which said wheels are respectively journaled and having body portions extending transversely of said structure in approximate parallelism with each other; a carriage supported upon said axles and positioned transversely of said structure a longitudinally extending beam structure fixed on the middle of said carriage and having its ends pivotally attached to central portions of said frames respectively to provide for variable angular divergence of said frames; and elevator means connected between one of said axles and said beam structure for raising and lowering said beam structure and frames with respect to said wheels.

3. A combination as in claim 2 wherein said wheels, axles and elevator means are disposed between said frames and said carriage is attached to said frames only through said beam structure and its pivotal attachments.

4. A combination as in claim 2 wherein the body portion of each axle is provided with a member adjustable with respect to the member on the other body portion to vary the relative angularity of said longitudinally extending arms and the relative height of said wheels with respect to said frames, adjusting means being carried by and connecting said members.

5. A combination as in claim 2 including stop means for adjustably limiting the lowering of said beam structure.

6. A combination as in claim 2 wherein one of said axles includes lever means directly underlying said beam structure, and said elevator means is disposed in an upstanding position between an end portion of said lever means and an overlying portion of said pivoted beam structure.

7. A wheeled disc harrow structure comprising: a forward disc frame; a rearward disc frame; a pair of ground wheels respectively disposed at the sides of said structure near the ends of said frames; cranlz axle means upon which said wheels are mounted; a carriage disposed transversely of said structure and supported by said axle means, said carriage comprising a rigid, transversely extending yoke; an overlying spacing and lifting beam having its ends pivotally attached respectively to middle portions of said frames to lift the latter, said frames being connected with said carriage solely through said pivotal connections with said beam, and the middle portion of said yoke being attached to an intermediate portion of said beam; lever means connected with said axle means and underlying said beam; and elevator means disposed between and connected with said lever means and said beam for raising and lowering said beam and frames with respect to said wheels.

8. A structure as in claim '7 wherein said frames are approximately balanced laterally with respect to their` respective points of attachnient to the ends of said beam.

9. A structure as in claim 8 wherein said elevator means comprises a vertically disposed hydraulic jack having its opposite ends respectively connected to an outer portion of said lever means and to an immediately overlying portion of said lifting beam, at least one end of said jack being connected by a relatively pivotal connection.

10. A wheeled disc harrow structure comprising: a forward disc frame; a rearward disc frame; a pair of ground wheels respectively disposed at the sides of said structure near the ends of said frames; axle means for said wheels; a carriage supported by said axle means; an overlying spacing and lifting median beam having its ends attached respectively to middle portions of said frames to lift the latter and having its middle portion supported and carried upon said carriage; lever means connected with said axle means and directly underlying said beam; and elevator means disposed between and connected with said lever means and said beam for raising and lowering said beam and frames with respect to said wheels, said elevator means comprising a vertically disposed hydraulic jack having its opposite ends repectively connected to an outer portion of said lever means and to an immediately overlying portion of said median beam, at least one end of said jack being connected by a relatively pivotal connection.

OTTO W. DOMRIES.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,830,422 Brice Nov. 3, 1931 2,126,446 Bordersen Aug. 9, '19-38 2,143,192 Goble Jan. 10, 1939 2,356,876 Newkirk Aug. 29, 1944 2,402,884 Gier June 25, 1946 2,469,622 Acton May `10, 1949 

